2, 4-dihydroxy benzophenone derivatives



UnitedStates-Patent O 2,891,996 7.,4-DIHYDROXY BENZOPHENONE DERIVATIVESGerald A. Clark, Midland, and CarlB. Havens, Hope; Mich., 'assignors toTheDowChemical Company Mid-v land, Mich., a corporation of Delaware NoDrawing. Application April 23, 1956 Serial No. 579,771

3 Claims. (Cl. 260-591) This invention relates to neworganicjcompoundsand to polymeric compositions containing the same. More particularly, itrelates to new organic compoundsfinding utility as light stabilizers forhaloethylene polymers.

, Haloethylene polymers. are known to be highly sensitive to the effectsof elevated temperattiresfandof light" and under prolonged exposure'to"heat and 'lightm'ay become sodegraded as tobe commercially useless. Ith'asjbeen common practice to blend certain compounds withthe polymer tostabilize it-against theidegradative, effec '{of heatand light.Several'of such com ounas',.,ne ler, are colored materials which impartan objectionable initial color to the stabilized composition and thusprevent the production of a commercially salable white composition.

Still other disadvantages of many of the previous compounds are a highodor level and volatility. Obviously, any odor in the stabilizer will betransferred to the stabilized composition. When volatile stabilizers areemployed, the stabilizers volatilize out of the composition, leaving thecomposition in time unprotected against the degradative elfects oflight, particularly ultra-violet light. In addition, all of thecompounds vary in their ability to absorb ultra-violet light and it isimpossible to predict the eflectiveness of any particular compound withany degree of certainty, and some of the compounds lose some of theireffectiveness for absorbing ultra-violet light over a prolonged periodof time.

In view of the above problems it would be desirable and it is theprincipal object of this invention to provide a new group of organiccompounds having the stated utility.

It is a further object to provide a polymeric composition stabilizedagainst the degradative effects of light by means of such compounds.

It is a still further object to provide a group of such compounds whichhave little or no color and have a low odor level.

Another object is to provide a group of such compounds which have lowvolatility.

The above and related objects are achieved by means of a group of2,4-dihydroxy benzophenone derivatives having the general formula:

includes stabilized thermoplastic compositions comprising such compoundsand haloethylene polymers.

. "ice I z I 1 As typical examples of the compounds which are within thescope of this invention may be mentioned:

3-acetyl-2,4-dihydroxy benzophenone 5-acetyl-2,4-dihydroxy benzophenone3,5-diacetyl-2,4-dihydroxy benzophenone 3-acety1-5-benzoyl-2,4-dihydroxybenzophenone 3-benzoyl-5-acetyl-2,4-dihydroxy benzophenone3-butyryl-2,4-dihydroxy benzophenone 3-caprylyl-2,4-dihydroxybenzophenone I 3-benzoyl-5-caprylyl-2,4-dihydroxy benzophenone3,5-dibutyryl-2,4-dihydroxy benzophenone 3,5-dicaprylyl-2,4-dihydroxybenzophenone.

9 The, compounds are easily prepared from'readily available materials.As a typical example of their preparation the procedure for preparing3-acetyl-2,4.-dihydroxy benzophenone will be described. A reactionmixture consisting of 0.25 mole of acetyl chloride, 0.25 mole of4benzoy1 resorcinol, and 0.5 mole aluminum chloride in 250 mls. oforthodichlorobenzenewas heated to C. for one hour. The reaction mixturewas then cooled and poured into cold dilute HCl. The solvent was removedby distillation and the product distilled in vacuo at 0.5 mm. Hg.Thefraction boiling at -187 C was collected, cooled, and recrystallizedthree times from 1,95 ."perclent ethyl alcohol. The 2-acetyl-4 benzoyl'resorcinol was'in the form of pale yellow crystals melting at 99.5to 100 C. The compound 3,5-diacetyl-2,4-dihydroxy benzophenone preparedin a similar manner was found to be a white crystalline solid melting atl5ll5l.5 C.

The compounds of this invention were evaluated as light stabilizers forhaloethylene polymers. Because of their low degree of odor and colorthey produced compositions that were more merchandisable thancompositions prepared from previous stabilizers. The eifectiveness ofthe stabilizers will be more apparent from the following illustrativeexample wherein all parts are by weight.

Example A series of samples was prepared from a basic formulationconsisting of 89.3 parts of a copolymer prepared from 85 percentvinylidene chloride and 15 percent vinyl chloride, 7 parts of apentaerythritol tetraester of a mixture of saturated fatty acids (ave.chain length=6) as a plasticizer, 1.7 parts of a phosphate heatstabilizer, and 1 part titanium dioxide as a pigment. One sample wasleft as a blank for comparison. To another was added 1 part of2-hydroXy-5-chlorobenzophenone, a known light stabilizer. To the otherswas added one part of the stabilizer of this invention. The samples werecompression molded to form sheets 0.01 inch thick. The moldings wereexposed to direct sunlight in the State of Arizona until an arbitrarystandard of browning had been reached.

It can be seen that the compounds of this invention are about twice aseifective as light stabilizers as is one of the most effectivepreviously known compounds.

The compounds will stabilize other haloethylene polymers includingvinylidene chloride polymers and copolymers and vinyl chloride polymersand copolymers. The most useful range of concentration of the newcompounds in such compositions is from 0.25 to 6 percent by 3. Acompound having the formula: I VCight. OH

-We claim:

1. As a new organic compound, a benzophenone de- 15 rivative having thegeneral formula:

OH 0 l X OH characterized by being a white crystalline solid having amelting point of ISL-151.5 C. H

References (Iitedl in the file of this patent wherein one X is anorganic acyl group derived from an UNITED STATES PATENTS aliphaticcarboxylic acid having from 1 to 8 carbon atoms and the remaining X isselected from the group 2364391 BOYFT 1941 consisting of hydrogen andorganic acyl groups derived 2,613,209 Bemefs 1952 from an aliphaticcarboxylic acid having from 1 to 8 2,659,709 Fenwlck 1953 carbon atom 202,686,812 Wynn Aug. 17, i954 2. A compound having the formula: 2,693,492Hoch 2: 1 5, 2,794,052 Gordon et a1 May 28, 1957 O OH O QTHER REFERENCESg. g Perkin et al.: Chem. Abstracts, vol. 1, p. 577 (1907). Bogert etal.: J. Am. Chem. Soc., vol. 52, pp. 837-50 Wittig et al.: Chem.Abstracts, vol. 25, p. 3634 (1931). characterized by being a pale yellowsolid and having Dischendorfer et al.: Chem. Abstracts, vol. 30,

a melting point of 99.5-1o0 c. 443-4 (1936).

1. AS A NEW ORGANIC COMPOUND, A BENZOPHENONE DERIVATIVE HAVING THEGENERAL FORMULA: